This invention relates in general to the field of manufacturing lenticular images and more particularly to detecting and measuring the pitch of lenticular material which is used for producing the lenticular images. More specifically, the invention relates to the detection of a change in pitch of the lenticular lenses as the material is transported in a scanning laser printer.
Lenticular images include an array of cylindrical lenses in a lenticular material and a sequence of spatially multiplexed images that are viewed throughout the lenticular material so that different ones of the multiplexed images are viewed at different angles by the viewer. One image effect produced by the lenticular image is a depth or 3D image where one eye views one image of a stereo pair or sequence from one angle and the other eye views another image from the stereo pair. Another image effect is a motion image where different images in a motion image sequence are viewed by changing the angle at which the image is viewed. Other effects that combine these two effects, or form collages of unrelated images that can be viewed from different viewing angles can be provided.
It has been proposed to create lenticular images by providing a lenticular material having a color photographic emulsion thereon. The spatially multiplexed images are exposed onto the lenticular media by a laser scanner and the material is processed to produce the lenticular image product. See for example, U.S. Pat. No. 5,697,006, issued Dec. 9, 1997 to Taguchi et al.
The image that is exposed on the lenticular media must be very precisely positioned under each lenticule. Unfortunately, the manufacturing and keeping tolerances of lenticular media result in significant changes in the pitch of the lenticular lenses in the media. If the pitch of the lenticular lenses on the material varies or is different from what is expected, the image quality will be comprised. There is a need therefore for an improved manufacturing process for making lenticular image products form lenticular media of the type having a lenticular lens array coated with photographic emulsion.
It is known to scan a non actinic laser beam across a lenticular array in a direction perpendicular to the axes of the lenticular lenses, and to sense the deflection of the beam by the lenticular lenses to produce an output clock for modulating a writing beam. See U.S. Pat. No. 5,681,676, issued Oct. 28, 1997 to Telfer et al.
It is one object of this invention to provide a method and apparatus for detecting and/or measuring any variation of lenticular pitch for the purpose of printing accurate images on the media. It is another object of the invention to provide a method and apparatus for compensating for such variations during manufacture of a lenticular image product.
The present invention is directed to overcoming one or more of the problems set forth above. Briefly summarized, according to one aspect of the present invention, a lenticular image product is formed from a lenticular material having an array of cylindrical lenses and a photographic emulsion coated thereon, by scanning the lenticular material with an intensity modulated first beam of light in a direction parallel to the long axes of the cylindrical lenses to form a latent lenticular image in the photographic emulsion. A second beam of light having a wavelength outside of the range of sensitivity of the photographic emulsion is focused into a spot smaller than the pitch of the cylindrical lenses onto the lenticular material. The lenticular material is moved through the beam in a direction perpendicular to the axes of the cylindrical lenses to provide a page scan motion of the lenticular material and to modulate the angle of reflection or refraction of the second beam of light. The position of the angularly modulated second beam of light is sensed and the sensed position is used to control the motion of the lenticular material.
These and other aspects, objects, features, and advantages of the present invention will be more clearly understood and appreciated from a review of the following detailed description of the preferred embodiments and appended claims, and by reference to the accompanying drawings.
The invention provides an accurate method for either mapping lenticular pitch or detecting pitch variations which can be compensated in a laser printer, thereby enabling efficient production of lenticular image products using lenticular media having photographic emulsion coated thereon.